Title

Photoionization Of Wide Bandgap Silicate Glasses By Ultrashort Ir Laser Pulses

Keywords

Keldysh theory; Laser-induced damage; Photoionization; Silicate glass; Ultrashort laser pulses

Abstract

We study the excitation of luminescence, photoionization, and laser-induced breakdown in a multi-component silicate photo-thermo-refractive (PTR) glass, and in fused silica. PTR glass is a high-purity homogeneous photosensitive alkali-silicate glass with intrinsic absorption edge at 5.8 eV (214 nm). Experiments are conducted with ultrashort laser pulses (100 fsec< τ < 1.5 psec) at the wavelengths 780 nm, 1430 nm, and 1550 nm. Filaments are observed inside both glasses and explained by a balance between Kerr self-focusing and free electron defocusing. Keldysh theory is used to model the formation of filaments and values of about 10 13 W/cm 2 for laser intensity and 10 19 cm -3 for free-electron density are estimated. Laser-induced damage by pulses at 1430 nm and 1550 nm is detected in fused silica and PTR glass by third harmonic generation due to the formation of an interface between a damage site and the surrounding glass matrix. It is found that there is an intensity range where luminescence and photoionization in both glasses occurs without laser-induced damage. © 2008 SPIE.

Publication Date

12-1-2008

Publication Title

Proceedings of SPIE - The International Society for Optical Engineering

Volume

7132

Number of Pages

713205-

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1117/12.804984

Socpus ID

62149092156 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/62149092156

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